Hot gas stirling cycle engine with in-line cylinders

ABSTRACT

In a Stirling cycle engine an even number of cylinders are disposed in line with two arcuate shaped heater pipe systems comprising a cylindrical combustion chamber disposed along the line adjacent to each pair of cylinders.

United States Patent [191 Berntell et al. Nov. 5, 1974 HOT GAS STIRLING CYCLE ENGINE WITH IN-LINE CYLINDERS [56] References Cited [75] inventors: John Osvald Berntell; Sven Rolf UNITED STATES PATENTS Hellmen, both of Malmo 2,817,950 12 1957 Van Weenen et al. 60/24 Sweden 2,828,601 4/1958 Meijer 60/24 [73] Assignee: Kommanditbolaget United Stirling (Sweden) AB & C M l Primary ExaminerEdgar W. Geoghcgan S d Assistant Examiner-Allen M. Ostrage Filed: Dec. 1972 Attorney, Agent, or Fu'mLaurence R. Brown [2!] 'Appl, No.: 315,475 57 ABSTRACT In a Stirling cycle engine an even number of cylinders [30] Foreign Application Priority Data are disposed in line with two arcuate shaped heater Dec. 18; 1971 Great Britain .2 58907/71 pip systems Comprising a cylindrical combustion chamber disposed along the line adjacent to each pair [52 US. Cl. 60/525 of cy [51] Int. Cl. F02g 1/04 58 Field o Search ..60/525 4 3 D'awmg F'gures HOT GAS STIRLING CYCLE ENGINE WITH IN-LINE CYLINDERS This invention relates to a hot gas engine of the double-acting type having an even number of in-line arranged cylinders, each accommodating a single piston connected to a common crank shaft, a number of regenerator-cooler units equal to the number of cylinders, heater pipe systems and cold gas connecting ducts all so arranged that an equal number of charges of working gas will perform one working cycle per revolution of the crank shaft.

Engines of this type should be designed as compact as possible and with connnections between the cylinders and regenerator-cooler units offering equal and small resistance in order to obtain a high degree of efficiency of the engine.

According to the present invention this is obtained thereby that in an engine of the type referred to above said heater pipe systems are arranged in pairs of two and are of arcuate shape and disposed so that each of said pairs has an approximately cylindrical configuration.

The invention will be described in more detail reference being made to the drawing in which FIG. 1 schematically shows an engine according to the invention as viewed from above,

FIG. 2 is a section along the line II-II in FIG. 1 and FIG. 3 shows another engine viewed from above.

The engine shown in FIGS. 1 and 2 comprises four cylinders l, 2, 3 and 4 each containing a piston 5 connected'to a piston rod 6 which in turn activates a crank shaft (not shown) via a connecting rod (not shown). Each cylinder is divided by its piston into an upper high temperature chamber 7 and a lower low temperature chamber 8. The upper chamber of each cylinder is connected via a system of heater pipes to a unit containing a regenerator 9 and a cooler 10. The lower chamber of each cylinder is connected to the cooler 10 of a different unit via a cold gas connecting duct 11.

The upper chambers of the cylinders l, 2, 3 and 4 are connected to the regenerators in the units 12, 13, 14 and 15 respectively via systems of heater pipes 16, 17, 18 and 19 respectively. The cold gas connecting ducts 11 are found in connecting elements 20 and 21 at one side of the cylinders 1 and 2 and in connecting elements 22 and 23 located at the opposite side of the cylinders 3 and 4.

The systems of heater pipes 16, 17, 18 and 19 are arranged in pairs of two and are of arcuate shape. Thus the systems 16 and 17 form a vertically disposed cylindrical construction well suitable for mounting in a surrounding combustion chamber (not shwon) for supplying heat to the high temperature chambers of the cylinders 1 and 2. Likewise the systems 18 and 19 form a similar cylindrical construction.

During operation of the engine each of four separate charges of working gas such as hydrogen or helium is passed between a high temperature working chamber and a low temperature working chamber. The four pistons of the engine are 90 angularly spaced at their connections to the crank shaft in such a way that a variation in gas pressure of each charge will occur. The variations are such that the expansion of the high temperature working chamber is 90 degrees in advance of the expansion of the low temperature working chamber and thus heat supplied at the high temperature working chamber and the heater pipes while removed at the coolers and the low temperature working chamber will be converted into mechanical energy as in conventional double-acting hot gas engines.

It will be understood that the above described engine designed according to the invention has the advantage of having two pairs of systems of heater pipes and thus only two combustion chambers are necessary. Also the heater pipes may be designed to have equal shape and equal flow resistance. Said flow resistance may be very low. The engine has also the advantage that the cold gas connecting ducts may be of equal very short length. Finally the said advantages are obtained with a conventional in-line design which is often attractive in many applications.

The design of FIG. 3 is a six-cylinder, in-line, doubleacting engine of basically the same type as that shown in FIGS. 1 and 2.

From one end of the engine the cylinders are desiggated by the reference numerals 31, 36,32, 35, 33 and At one side of the line of cylinders three regeneratorcooler units 41, 42 and 43 are located. Three other regenerator-cooler units 44, 45 and 46 are located at the opposite side of the line of cylinders.

The cylinders and the units of coolers and regenerators are interconnected by pairs of heater pipes and by cold gas connecting ducts.

Thus the cylinder 31 is connected to the cylinder 32 via the unit 41. The cylinder 32 is connected to the cylinder 33 via the unit 42. The cylinder 33 is connected to the cylinder 34 via the unit 43. The cylinder 34 is connected to the cylinder 35 via the unit 44. The cylinder 35 is connected to cylinder 36 via the unit and the cylinder 36 is connected to the cylinder 31 via the unit 46.

The six-cylinder engine briefly described and shown in FIG. 3 will contain six pistons being angularly spaced at their connections to a common crank shaft. The expansion of a high temperature working chamber will be 60 in advance of the'low temperature working chamber with which it is connected through a unit of a regenerator and a cooler.

What is claimed is:

1. A Stirlin cycle engine comprising in combination an even num er of cylinders all of which are disposed in-line, a regenerator-cooler unit for each cylinder, and heater pipe systems connected from each cylinder to a corresponding regenerator unit arranged with heater pipes disposed in an arc with the pipes from two adjacent cylinders disposed in a cylindrical arrangement comprising a combustion chamber, cold gas connecting ducts of the same length connected from each regenerator-cooler unit thereby being disposed tolead from said in-line cylinders to said regenerator units disposed on opposite sides thereof.

2. An engine as defined in claim 1 having at least one regenerator unit disposed on one side of said in-line cy inders and at least one regenerator unit disposed on the other side of said in-line cylinders.

3. An engine as defined in claim 2 having at least four cylinders wherein a pair of regenerator units for two adjacent c linders are disposed on one side of said cylinders an another air of regenerator units for two other cylinders are isposed on the other side of said cylinders.

4. An engine as defined in claim 3 having six cylinders wherein a single regenerator unit is disposed along said line of cylinders at a position opposite each pair of said regenerator uni ts. 

1. A Stirling cycle engine comprising in combination an even number of cylinders all of which are disposed in-line, a regenerator-cooler unit for each cylinder, and heater pipe systems connected from each cylinder to a corresponding regenerator unit arranged with heater pipes disposed in an arc with the pipes from two adjacent cylinders disposed in a cylindrical arrangement comprising a combustion chamber, cold gas connecting ducts of the same length connected from each regenerator-cooler unit thereby being disposed to lead from said in-line cylinders to said regenerator units disposed on opposite sides thereof.
 2. An engine as defined in claim 1 having at least one regenerator unit disposed on one side of said in-line cylinders and at least one regenerator unit disposed on the other side of said in-line cylinders.
 3. An engine as defined in claim 2 having at least four cylinders wherein a pair of regenerator units for two adjacent cylinders are disposed on one side of said cylinders and another pair of regenerator units for two other cylinders are disposed on the other side of said cylinders.
 4. An engine as defined in claim 3 having six cylinders wherein a single regenerator unit is disposed along said line of cylinders at a position opposite each pair of said regenerator units. 